Design and ocular tolerance of flurbiprofen loaded ultrasound-engineered NLC

Role of architecture of N-oxide surfactants in the design of nanoemulsions for Candida skin infection

In this work we present comprehensive research on the formation, stability and structural properties of oil-in-water (o/w) nanoemulsions with the ability for topical administration, penetration of the skin and acting as antifungal agents against C. albicans. The studied nanoemulsions were composed of different ratios of double-head - single-tail surfactants {1-bis{[3-(N,N-dimethylamino)ethyl]amido}alkane-di-N-oxides (C_n-MEDA), N,N-bis[3,3'-(dimethyl-amino)propyl]alkyl-amide di-N-oxides (C_n(DAPANO)₂} and single-head - single-tail surfactants {2-(alkanoylamino)-ethyldimethyl-amine-N-oxides (C_n-EDA), and 3-(alkanoylamino) propyldimethylamine-N-oxides, (C_n-PDA)} added to the oil {isooctane IO, isopropyl myristate IPM or glyceryl monocaprylate GM as (O)} and to the water phase (W). The phase behavior of the systems was examined by a titration method. Morphology of the resulting colloids was characterized by scanning and transmission electron microscopy, the particle size and size distributions determined by dynamic light scattering, and kinetic stability by multiple light scattering. While both surfactant types resulted in quite stable nanoemulsions, the systems formed using a single-headed one-tail surfactant were slightly more stable with GM or IPM. The microenvironmental properties of the nanoemulsions were studied by an electron paramagnetic resonance technique to distinguish the molecular dynamics of the different spin probes localized in the particular regions of the surfactant layers, depending on the surfactant structure and the system preparation. Skin permeation studies were performed to monitor transport through the skin, and changes in skin structure were followed using differential scanning calorimetry. Moreover, the activities of curcumin-loaded nanoemulsions stabilized by N-oxide surfactants against Candida albicans fungus were evaluated. To estimate in vitro efficacy, the suitability of an N-oxide nanoemulsion dressing against wound infection with biofilm C. albicans was assessed according to the Antibiofilm Dressing's Activity Measurement. We expect that the nanoemulsion formulations tested in this study will have potential for application as topical delivery systems for pharmaceutically active compounds in skin-related conditions.

Development of Betamethasone Dipropionate-Loaded Nanostructured Lipid Carriers for Topical and Transdermal Delivery

Introduction

Betamethasone dipropionate is a highly effective corticosteroid anti-inflammatory. However, the main drawback of its topical use is the limited skin penetration into deeper skin layers. Also, its systemic use has shown many side effects.

Objective

The goal of this research was to formulate betamethasone dipropionate in nanostructured lipid carriers (NLC) formulae that contain oleic acid to aid its penetration to deeper skin layers and to aid absorption to local regions upon topical application.

Methods

NLC formulae were prepared by high shear homogenization then sonication. Formulae were characterized for their particle size, size distribution, electric potential, occlusion factor, entrapment efficiency, drug loading, transmission electron microscopy, in vitro drug release, and ex vivo skin penetration. Compatibility of ingredients with drug was tested using differential scanning calorimetry. Formulae were shown to have appropriate characteristics. NLC formulae were superior to traditional topical formulation in drug release.

Results

Upon testing ex vivo skin penetration, betamethasone dipropionate prepared in NLC formulae was shown to penetrate more efficiently into skin layers than when formulated as a traditional cream. NLC formulation that contained higher percentage of oleic acid showed higher penetration and higher amount of drug to pass through skin.

Conclusion

In general, NLC with lower oleic acid percentage was shown to deliver betamethasone dipropionate more efficiently into deeper skin layers while that of a higher oleic acid percentage was shown to deliver the drug more efficiently into deeper skin layers and through the skin, transdermally.

Hybrid Nanostructured Films for Topical Administration of Simvastatin as Coadjuvant Treatment of Melanoma

This work aims at (1) assessing the potential of repurposing simvastatin (SV) to support the most common therapies against melanoma and (2) developing an innovative topical adhesive film, composed by chitosan-coated nanostructured lipid carriers (Ch-NLC) used as drug vehicle. A factorial design approach was employed as the basis for the formulation development. Optimized Ch-NLC displayed a particle size of 108 ± 1 nm, a polydispersity index of 0.226, a zeta potential of 17.0 ± 0.6 mV, as well as an entrapment efficiency of 99.86 ± 0.08%, and SV loading of 14.99 ± 0.01%. The performance of SV-Ch-NLC films was assessed in terms of release, permeation, and adhesion, as critical quality attributes. Cutaneous tolerability and in vitro cytotoxicity studies were performed to warrant film safety and drug effectiveness, respectively. The topical films provided a sustained release kinetic profile of SV and were classified as nonirritant systems. The encapsulation of SV increased cytotoxicity in melanoma cells. The key role of squalene as nanostructuring agent of the lipid nanoparticle matrix and as permeation enhancer was highlighted, suggesting its key action for potentiating skin permeation and uptake into melanoma cells. Topical SV-Ch-NLC films are thus able to provide an in situ extended drug delivery and useful as coadjuvant treatment of melanoma skin lesions.

Advances in ophthalmic preparation: the role of drug nanocrystals and lipid-based nanosystems

Nanocrystals and lipid-based nanosystems have the potential to play a crucial role in a significant shift in the treatment of ophthalmic diseases. These drug delivery systems allow overcoming the barriers imposed by anatomy and physiology of the organ of vision. This review aims to present new perspectives for these innovative preparations, emphasising the applications of the nanocrystal and lipid-based nanosystem while outlining their advantages and the drawbacks. The in vivo performance of the lipid-based nanosystems was highlighted. Lipid-based nanosystems and nanocrystals showed a prolonged effect, improved ocular bioavailability, upper therapeutic efficacy, higher permeation, prolonged residence time, and sustained drug release, compared to the current applications. Well-established and innovative developments updates of these systems are highlighted herein.

Xanthan gum assisted foam fractionation for the recovery of casein from the dairy wastewater

Casein was the major protein in the milk of mammals and it was massively lost in the discharged wastewater during dairy product manufacture. This work was aimed at recovering casein from the dairy wastewater by using foam fractionation. In order to improve the foam stability, xanthan gum was used as the foam stabilizer based on the association between protein and polysaccharide. The results of the scanning electron microscope (SEM) and fluorescence emission spectrum suggested that casein could be associated with xanthan gum primarily through electrostatic attraction, which was significantly affected by pH. Moreover, the introduction of xanthan gum had a marked impact on the surface tension, foam ability, foam stability, turbidity, zeta potential and average particle size of casein dispersion. Foam fractionation was performed under the suitable operation condition of pH 6.0, loading liquid volume 400 mL, amount ratio of casein and xanthan gum 1:2, volumetric airflow rate 100 mL/min and pore diameter of gas distributor 0.180 mm. The enrichment ratio and the recovery percentage of casein reached as high as 16.81 and 86.51%, respectively. This work is expected to provide a cost-effective method to recover the trace desired material through improving foam stability based on intermolecular forces.Research highlightsFoam fractionation has been proposed to recover casein from dairy wastewater.Xanthan gum has been used to improve the foam stability of casein.The main interaction between casein and xanthan gum was an electrostatic attraction.Xanthan gum contributed to weakening the flowability of interstitial liquid.

Dispersible Biopolymer Particles Loaded with Lactase as a Potential Delivery System To Control Lactose Hydrolysis in Milk

To deliver lactase in milk, dispersible capsules were fabricated by anti-solvent precipitation of zein to form a zein-lactase core and a shell of low-methoxyl sugar beet pectin cross-linked by Ca²⁺, involving electrostatic, hydrophobic, hydrogen-bonding, and Ca²⁺-bridging forces. At optimal conditions, an encapsulation efficiency of 93.0% and Z-average diameter of 652.7 nm were observed, and spherical particles smaller than 200 nm were observed in scanning electron microscopy. Contrasting with complete hydrolysis within 1 week by unencapsulated lactase, 50 units/mL encapsulated lactase resulted in 33.1 and 40.0% lactose hydrolysis in whole and skim milk, respectively, after 3 weeks of storage at 4 °C. In separate in vitro digestion assays, 50 units/mL encapsulated lactase resulted in 100% lactose hydrolysis in milk, contrasting with negligible activity by free lactase. These findings suggest the potential of the studied biopolymer particles to incorporate lactase in milk, prevent lactose hydrolysis during storage, and hydrolyze lactose in milk after ingestion.

Development of Halobetasol-loaded nanostructured lipid carrier for dermal administration: Optimization, physicochemical and biopharmaceutical behavior, and therapeutic efficacy

Halobetasol propionate (HB) is considered a super potent drug in the group of topical corticosteroids. HB has anti-inflammatory activity, vasoconstriction properties, and due to its high skin penetration, it can cause systemic side effects. To improve its characteristics, enhance topical effectiveness and reduce penetration to systemic circulation, a study to optimize and characterize a HB-loaded lipid nanocarrier (HB-NLC) has been made by high-pressure homogenization method. The formulation is composed by HB, surfactant, glyceryl distearate and capric glycerides. The optimized HB-NLC containing 0.01% of HB and 3% of total lipid shows an average size below 200 nm with a polydispersity index ≪0.2 and an encapsulation efficiency ≫90%. The in vitro and in vivo tests indicate that the HB-NLC is not toxic, is well tolerated and has an anti-inflammatory effect because they decrease the production of Interleukins in keratinocytes and monocytes. HB-NLC is considered an alternative treatment for skin inflammatory disorders.

Nanoemulsion Based Vehicle for Effective Ocular Delivery of Moxifloxacin Using Experimental Design and Pharmacokinetic Study in Rabbits

Nanoemulsion is one of the potential drug delivery strategies used in topical ocular therapy. The purpose of this study was to design and optimize a nanoemulsion-based system to improve therapeutic efficacy of moxifloxacin in ophthalmic delivery. Moxifloxacin nanoemulsions were prepared by testing their solubility in oil, surfactants, and cosurfactants. A pseudoternary phase diagram was constructed by titration technique and nanoemulsions were obtained with four component mixtures of Tween 80, Soluphor^® P, ethyl oleate and water. An experiment with simplex lattice design was conducted to assess the influence of formulation parameters in seven nanoemulsion formulations (MM1–MM7) containing moxifloxacin. Physicochemical characteristics and in vitro release of MM1–MM7 were examined and optimized formulation (MM3) was further evaluated for ex vivo permeation, antimicrobial activity, ocular irritation and stability. Drug pharmacokinetics in rabbit aqueous humor was assessed for MM3 and compared with conventional commercial eye drop formulation (control). MM3 exhibited complete drug release in 3 h by Higuchi diffusion controlled mechanism. Corneal steady state flux of MM3 (~32.01 µg/cm²/h) and control (~31.53 µg/cm²/h) were comparable. Ocular irritation study indicated good tolerance of MM3 and its safety for ophthalmic use. No significant changes were observed in the physicochemical properties of MM3 when stored in the refrigerator for 3 months. The greater aqueous humor concentration (C_max; 555.73 ± 133.34 ng/mL) and delayed T_max value (2 h) observed in MM3 suggest a reduced dosing frequency and increased therapeutic efficacy relative to control. The area under the aqueous humor concentration versus time curve (AUC_{0–8 h}) of MM3 (1859.76 ± 424.51 ng·h/mL) was ~2 fold higher (p < 0.0005) than the control, suggesting a significant improvement in aqueous humor bioavailability. Our findings suggest that optimized nanoemulsion (MM3) enhanced the therapeutic effect of moxifloxacin and can therefore be used as a safe and effective delivery vehicle for ophthalmic therapy.

Preparation, characterisation and in vitro antibacterial property of ciprofloxacin-loaded nanostructured lipid carrier for treatment of Bacillus subtilis infection

Context: In this study, controlled ciprofloxacin (CIPRO) nanostrustructured lipid carriers of Precirol^® ATO 5/Transcutol^® HP (batch A) and tallow fat/Transcutol^® HP (batch B) was carreid out. Objective: The aim was to improve solubility and bioavailability of CIPRO. Objective: Study of controlled ciprofloxacin (CIPRO) nanostructured lipid carriers of Precirol^® ATO 5/Transcutol^® HP (batch A) and tallow fat/Transcutol^® HP (batch B). Methods: CIPRO concentrations C_1-5 (0.0, 0.2, 0.5, 0.8, and 1.0% w/w) as AC_1-5 and BC_1-5 were prepared by hot homogenisation and characterised by zetasizer, differential scanning calorimetry, Fourier transform infra-red spectroscopy, in vitro drug release and growth inhibitory zone diameter (IZD) on agar-seeded Bacillus subtilis. Results: AC₅ achieved polydispersed particles of ∼605 nm, 92% encapsulation efficiency (EE) and -28 mV similar to BC₅ (∼789 nm, 91% EE, and -31 mV). Crystallinity indices (AC₅ and BC₅) were low at 3 and 5%, respectively. CIPRO release in AC₅ was ∼98% in SGF (pH 1.2) and BC₅ similarly ∼98% in SIF (pH 6.8). Conclusions: AC₅ had superior growth inhibition of B. subtilis at lower concentration (1.2 µg/mL) than BC₅ and CIPRO controls; hence could serve as possible sustained delivery system of CIPRO.

Ultrasound-Assisted Facile Synthesis of Nanostructured Hybrid Vesicle for the Nasal Delivery of Indomethacin: Response Surface Optimization, Microstructure, and Stability

This work is devoted to design a novel nanostructured hybrid vesicle (NHV) made of lecithin and an acrylate/C10-C30 alkyl acrylate for the nasal delivery of a model active indomethacin (IND), and further to probe its microstructure, intermolecular interactions, drug release behavior, ex vivo permeation, and stability. NHVs were prepared by cavitation technology employing RSM-based central composite design (CCD). Amount of lecithin (X₁), power of ultrasound (X₂), and sonication time (X₃) were selected as three independent variables while the studied response included Z-Avg (nm), polydispersity index (PDI), and zeta potential (mV). The designed system (NHV) was investigated through dynamic (DLS) and electrophoretic light scattering (ELS), attenuated total reflectance (ATR-FTIR), oscillatory measurement (stress and frequency sweep), and transmission electron microscopy (TEM). CCD was found useful in optimizing NHV. An optimized formulation (S6) had Z-Avg 80 nm, PDI 0.2, and zeta potential of - 43.26 mV. Morphology investigation revealed spherical vesicles with smaller TEM diameters (the largest particle being 52.26 nm). ATR analysis demonstrated significant intermolecular interactions among the drug (IND) and the components of vesicles. The designed vesicles had an elastic predominance and displayed supercase II (n > 1) type of drug release. Besides, the vesicles possessed potential to transport IND across the nasal mucosa with the steady-state flux (μg/cm²/h) and permeability coefficient (cm/h) of 26.61 and 13.30 × 10^-3, respectively. NHV exhibited an exceptional stability involving a combination of electrostatic and steric interactions while the histopathology investigation confirmed their safety for nasal administration.

Development of Pranoprofen Loaded Nanostructured Lipid Carriers to Improve Its Release and Therapeutic Efficacy in Skin Inflammatory Disorders

Pranoprofen (PF)-loaded nanostructured lipid carriers (NLCs), prepared using a high-pressure homogenization method, have been optimized and characterized to improve the biopharmaceutical profile of the drug. The optimized PF-NLCs exhibited physicochemical characteristics and morphological properties that were suitable for dermal application. Stability assays revealed good physical stability, and the release behavior of PF from these NLCs showed a sustained release pattern. Cell viability results revealed no toxicity. Ex vivo human skin permeation studies in Franz diffusion cells were performed to determine the influence of different skin penetration enhancers (pyrrolidone, decanol, octanoic acid, nonane, menthone, squalene, linoleic acid, and cineol) on skin penetration and retention of PF, being the highest dermal retention in the presence of linoleic acid. The selected formulations of NLCs exhibited a high retained amount of PF in the skin and no systemic effects. In vivo mice anti-inflammatory efficacy studies showed a significant reduction in dermal oedema. NLCs containing linoleic acid presented better anti-inflammatory efficacy by decreasing the production of interleukins in keratinocytes and monocytes. The biomechanical properties of skin revealed an occlusive effect and no hydration power. No signs of skin irritancy in vivo were detected. According to these results, dermal PF-NLCs could be an effective system for the delivery and controlled release of PF, improving its dermal retention, with reduced dermal oedema as a possible effect of this drug.

Astaxanthin-Loaded Nanostructured Lipid Carriers for Preservation of Antioxidant Activity

Astaxanthin is a xanthophyll carotenoid showing efficient scavenging ability and represents an interesting candidate in the development of new therapies for preventing and treating oxidative stress-related pathologies. However, its high lipophilicity and thermolability often limits its antioxidant efficacy in human applications. Here, we developed a formulation of lipid carriers to protect astaxanthin’s antioxidant activity. The synthesis of natural astaxanthin-loaded nanostructured lipid carriers using a green process with sunflower oil as liquid lipid is presented. Their antioxidant activity was measured by α-Tocopherol Equivalent Antioxidant Capacity assay and was compared to those of both natural astaxanthin and α-tocopherol. Characterizations by dynamic light scattering, atomic force microscopy, and scattering electron microscopy techniques were carried out and showed spherical and surface negative charged particles with z-average and polydispersity values of ~60 nm and ~0.3, respectively. Astaxanthin loading was also investigated showing an astaxanthin recovery of more than 90% after synthesis of nanostructured lipid carriers. These results demonstrate the capability of the formulation to stabilize astaxanthin molecule and preserve and enhance the antioxidant activity.

Skin-controlled release lipid nanosystems of pranoprofen for the treatment of local inflammation and pain

Aim: The design and development of pranoprofen (PF) nanostructured lipid carriers (NLCs) for topical treatment of local inflammation and pain. Materials & methods: PF-NLCs were designed and optimized by central rotatable composite design. A physicochemical characterization was addressed. Release and skin permeation were performed in Franz diffusion cells. In vivo anti-inflammatory efficacy was assayed in mice and tolerance study in humans. Results: PF-NLCs F7 and F10 provided sustained release, good stability and optimal skin retention avoiding systemic undesired side effects. Anti-inflammatory activity was enhanced, suggesting an improved efficacy as compared with standard formulation. No skin irritancy was detected. Conclusion: Topical PF-NLCs F7 and F10 could be effective and safe new therapeutic tools for the treatment of local inflammation and pain.

[Formula: see text]

Astaxanthin-alpha tocopherol nanoemulsion formulation by emulsification methods: Investigation on anticancer, wound healing, and antibacterial effects

Emulsion-based delivery systems have been fabricated and developed to increase the bioavailability of astaxanthin and alpha-tocopherol as active compounds for various biomedical applications. Astaxanthin-alpha tocopherol nanoemulsion (ATNE) is well known for its potential 6.-6.30 effect. The current study investigated ATNE by spontaneous (SENE) and ultrasonication emulsification (USNE) methods to optimally fabricate oil/water nanoemulsion characterized for biomedical applications. The two methods were compared by using a response surface method of 3-level Box-Behnken design (BBD) with significant factors. Transmission electron microscopy (TEM) confirmed spherical-shaped nanoemulsion from SENE and USNE methods and dynamic light scattering (DLS) proved the good stability of the fabricated nanoemulsion. Cytotoxicity studies on three different cancer cells confirmed that the nanoemulsion at higher concentrations was more toxic than one at lower concentrations by accompanying a significant decrease in the cellular viability after 24 and 48 h of exposure. The wound-healing potential using scratch assay evidenced faster healing effect of the nanoemulsion. Both minimal inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) methods confirmed significant antibacterial activity to disrupt the integrity of the bacterial cell membrane. The current results suggested that ATNE act as effectively targeted drug delivery vehicles in the future for cancer treatment applications due to its significant results of anticancer, wound healing, and antimicrobial effects.

Mediterranean essential oils as precious matrix components and active ingredients of lipid nanoparticles

Essential oils are recognized as valuable active pharmaceutical ingredients attributed to a set of biological properties, which include antibacterial, antifungal, antiviral, antioxidant, anticancer, immune-modulatory, analgesic and anti-inflammatory activities. Their use in pharmaceutics is however compromised by their limited water solubility and low physicochemical stability (i.e. volatility, oxidation). In order to overcome these limitations, we aimed to develop nanostructured lipid carriers (NLC) as delivery systems for Mediterranean essential oils, in particular Rosmarinus officinalis L., Lavandula x intermedia "Sumian", Origanum vulgare subsp. hirtum and Thymus capitatus essential oils, selected on the basis of their antioxidant and anti-inflammatory activities. NLC composed of Softisan (as solid lipid) have been produced by phase inversion temperature (PIT) and high-pressure homogenization (HPH), using two different emulsifiers systems. Particles have been further characterized for their mean particle size, polydispersity, zeta potential, morphology and chemical interactions. Best NLC formulations were obtained with Kolliphor/Labrafil as surfactants, and using Rosmarinus, Lavandula and Origanum as essential oils (PDI between 0.126 and 0.141, Zave < 200 nm). Accelerated stability studies have also been carried out to estimate the effect of the production method and surfactant composition on the long-term stability of EOs-loaded NLC. In vitro biological cell viability and anti-inflammatory activities were evaluated in Raw 264.7 cells (macrophage cell line), while in vitro antioxidant activity was checked by DPPH assay. Lavandula and Rosmarinus NLC were shown to be the most biocompatible formulations up to a concentration of 0.1% (v/v), whereas they were able to induce a dose-dependent anti-inflammatory activity in the order Lavandula > Rosmarinus ≥ Origanum.

Epigallocatechin-3-gallate loaded PEGylated-PLGA nanoparticles: A new anti-seizure strategy for temporal lobe epilepsy

Temporal lobe epilepsy is the most common type of pharmacoresistant epilepsy in adults. Epigallocatechin-3-gallate has aroused much interest because of its multiple therapeutic effects, but its instability compromises the potential effectiveness. PEGylated-PLGA nanoparticles of Epigallocatechin-3-gallate were designed to protect the drug and to increase the brain delivery. Nanoparticles were prepared by the double emulsion method and cytotoxicity, behavioral, Fluoro-Jade C, Iba1 and GFAP immunohistochemistry studies were carried out to determine their effectiveness. Nanoparticles showed an average size of 169 nm, monodisperse population, negative surface charge, encapsulation efficiency of 95% and sustained release profile. Cytotoxicity assays exhibited that these nanocarriers were non-toxic. Behavioral test showed that nanoparticles reduced most than free drug the number of epileptic episodes and their intensity. Neurotoxicity and immunohistochemistry studies confirmed a decrease in neuronal death and neuroinflammation. In conclusion, Epigallocatechin-3-gallate PEGylated-PLGA nanoparticles could be a suitable strategy for the treatment of temporal lobe epilepsy.

Novel nanosystems for the treatment of ocular inflammation: Current paradigms and future research directions

Ocular discomforts involve anterior/posterior-segment diseases, symptomatic distress and associated inflammations and severe retinal disorders. Conventionally, the formulations such as eye drops, eye solutions, eye ointments and lotions, etc. were used as modalities to attain relief from such ocular discomforts. However, eye allows limited access to these traditional formulations due to its unique anatomical structure and dynamic ocular environment and therefore calls for improvement in disease intervention. To address these challenges, development of nanotechnology based nanomedicines and novel nanosystems (liposomes, cubosomes, polymeric and lipidic nanoparticles, nanoemulsions, spanlastics and nano micelles) are currently in progress (some of them are already marketed such as Eye-logic liposomal eye spray@Naturalife, Ireland). Today, it is one of the central concept in designing more accessible formulations for deeper segments of the eyes. These nanosystems has largely enabled the availability of medicaments at required site in a required concentration without inversely affecting the eye tissues; and therefore, attaining the excessive considerations from the formulation scientists and pharmacologists worldwide. The entrapment of drugs, genes, and proteins inside these novel systems is the basis that works at the bio-molecular level bestows greater potential to eradicate disease causatives. In this review, we highlighted the recent attempts of nanotechnology-based systems for treating and managing various ocular ailments. The progress described herein may pave the way to new, highly effective and vital ocular nanosystems.

Development and Optimisation of Spironolactone Nanoparticles for Enhanced Dissolution Rates and Stability

Stable solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) formulations to enhance the dissolution rates of poorly soluble drug spironolactone (SP) were being developed. Probe ultra-sonication method was used to prepare SLNs and NLCs. All NLCs contained stearic acid (solid lipid carrier) and oleic acid (liquid lipid content), whereas, SLNs were prepared and optimised by using the solid lipid only. The particles were characterised in terms of particle size analysis, thermal behaviour, morphology, stability and in vitro release. The zeta sizer data revealed that the increase in the concentration of oleic acid in the formulations reduced the mean particle size and the zeta potential. The increase in concentration of oleic acid from 0 to 30% (w/w) resulted in a higher entrapment efficiency. All nanoparticles were almost spherically shaped with an average particle size of about ∼170 nm. The DSC traces revealed that the presence of oleic acid in the NLC formulations resulted in a shift in the melting endotherms to a higher temperature. This could be attributed to a good long-term stability of the nanoparticles. The stability results showed that the particle size remained smaller in NLC compared to that of SLN formulations after 6 months at various temperatures. The dissolution study showed about a 5.1- to 7.2-fold increase in the release of the drug in 2 h compared to the raw drug. Comparing all nanoparticle formulations indicated that the NLC composition with a ratio of 70:30 (solid:liquid lipid) is the most suitable formulation with desired drug dissolution rates, entrapment efficiency and physical stability.

Development and characterization of nanostructured lipid carriers based chitosan thermosensitive hydrogel for delivery of dexamethasone

This study aims to explore a novel composite thermosensitive in situ gelling formulation which the nanostructured lipid carriers (NLC) was incorporated into hydroxypropyltrimethyl ammonium chloride chitosan (HACC)-based hydrogels, and the resulting formulation investigated for its potential to act as a potential sustained ocular delivery system. NLC formulation loaded with dexamethasone (DXM) were prepared using the melt-emulsification method. The particle size, zeta potential, encapsulation efficiency, and morphological properties of the NLC were characterized. The HACC was synthesized and structure was analyzed by FT-IR and ¹H NMR. A thermosensitive hydrogel was designed and prepared by simply mixing HACC and β-glycerophosphate (β-GP). The obtained formulation showed a rapid solution-to-gel transition at 35°C. The NLC were then incorporated in HACC/β-GP hydrogel to form a NLC-loaded hydrogel carrier. In vitro release studies, 88.65% of total DXM was released from the NLC-HACC/GP gel within 3days, indicating DXM-based NLC-gel could release drug sustainably. Taken together, DXM-based NLC-HACC/GP gel is a promising drug delivery system.

Ivermection-loaded solid lipid nanoparticles: preparation, characterisation, stability and transdermal behaviour

To avoid potential systematical toxicity, solid lipid nanoparticles (SLNs) were prepared as a vehicle for transdermal delivery of ivermectin (IVM) using hot homogenisation followed by ultrasonic method. The as-prepared SLNs were approximately spherical shape with good stability. IVM was encapsulated in amorphous form within SLNs and displayed prolonged release from SLNs without burst release due to high encapsulation efficiency (EE). The cumulative permeation of IVM across excised rat skin from SLNs was significantly increased compared to the ivermection suspension. These results indicated that the proposed SLNs can be considered as an efficient carrier for dermal delivery of IVM to effectively treat scabies.

Phospholipid complex enriched micelles: A novel drug delivery approach for promoting the antidiabetic effect of repaglinide

To enhance the oral antidiabetic effect of repaglinide (RG), a newly emerging approach, based on the combination of phospholipid complexation and micelle techniques, was employed. Repaglinide-phospholipid complex (RG-PLC) was prepared by the solvent-evaporation method then characterized using Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XPRD). The results revealed obvious disappearance of the characteristic peaks of the prepared RG-PLCs confirming the formation of drug-phospholipid complex. RG-PLC enriched micelles (RG-PLC-Ms) were prepared by the solvent-evaporation technique employing poloxamer 188 as surfactant. The prepared RG-PLC-Ms showed high drug encapsulation efficiencies (93.81-99.38%), with nanometric particle diameters (500.61-665.32nm) of monodisperse distribution and high stability (Zeta potential < -29.8mV). The in vitro release of RG from RG-PLC-Ms was pH-dependant according to the release media. A higher release pattern was reported in pH=1.2 compared to a more retarded release in pH=6.8 owing to two different kinetics of drug release. Oral antidiabetic effect of two optimized RG-PLC-M formulations was evaluated in an alloxan-induced diabetic rat model for 7-day treatment protocol. The two investigated formulations depicted normal blood glucose, serum malondialdehyde and insulin levels as well as an improved lipid profile, at the end of daily oral treatment, in contrast to RG marketed tablets implying enhanced antidiabetic effect of the drug. Hence, phospholipid-complex enriched micelles approach holds a promising potential for promoting the antidiabetic effect of RG.

Lipid nanoparticles (SLN, NLC): Overcoming the anatomical and physiological barriers of the eye - Part II - Ocular drug-loaded lipid nanoparticles

In the recent decades, various controlled delivery systems have been introduced with the aim to improve solubility, stability and bioavailability of poorly absorbed drugs. Among all, lipid nanoparticles gather interesting properties as drug or gene delivery carriers. These systems, composed either of solid lipids (SLN) or of solid and liquid lipids (NLC) stabilized with surfactants, combine the advantages of other colloidal particles such as polymeric nanoparticles, fat emulsions and liposomes avoiding their main disadvantages. Lipid nanoparticles represent an interesting approach for eye drug delivery as they can improve the corneal absorption of drugs enhancing their bioavailability. The Generally Recognized as Safe status of formulation excipients, the scaling-up facilities and the possibility of sterilization, make them suitable for industrial production. In this review, the latest findings, potential applications, and challenges related to the use of lipid nanoparticles for ocular drug delivery are comprehensively discussed.

Preclinical safety of solid lipid nanoparticles and nanostructured lipid carriers: Current evidence from in vitro and in vivo evaluation

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) were designed as exceptionally safe colloidal carriers for the delivery of poorly soluble drugs. SLN/NLC have the particularity of being composed of excipientsalready approved for use in medicines for human use, which offers a great advantage over any other nanoparticulate system developed from novel materials. Despite this fact, any use of excipients in new route of administration or in new dosage form requires evidence of safety. After 25 years of research on SLN and NLC, enough evidence on their preclinical safety has been published. In the present work, published data on in vitro and in vivo compatibility of SLN/NLC have been surveyed, in order to provide evidence of high biocompatibility distinguished by intended administration route. We also identified critical factors and possible weak points in SLN/NLC formulations, such as the effect of surfactants on the cell viability in vitro, which should be considered for further development.

Polymeric nanocapsules with up-converting nanocrystals cargo make ideal fluorescent bioprobes

An innovative approach for up-converting nanoparticles adaptation for bio-related and theranostic applications is presented. We have successfully encapsulated multiple, ~8 nm in size NaYF₄ nanoparticles inside the polymeric nanocarriers with average size of ~150 nm. The initial coating of nanoparticles surfaces was preserved due to the hydrophobic environment inside the nanocapsules, and thus no single nanoparticle surface functionalization was necessary. The selection of biodegradable and sugar-based polyelectrolyte shells ensured biocompatibility of the nanostructures, while the choice of Tm³⁺ and Yb³⁺ NaYF₄ nanoparticles co-doping allowed for near-infrared to near-infrared bioimaging of healthy and cancerous cell lines. The protective role of organic shell resulted in not only preserved high up-converted emission intensity and long luminescence lifetimes, without quenching from water environment, but also ensured low cytotoxicity and high cellular uptake of the engineered nanocapsules. The multifunctionality of the proposed nanocarriers is a consequence of both the organic exterior part that is accessible for conjugation with biologically important molecules, and the hydrophobic interior, which in future application may be used as a container for co-encapsulation of inorganic nanoparticles and anticancer drug cargo.

Potential advantages of a novel chitosan-N-acetylcysteine surface modified nanostructured lipid carrier on the performance of ophthalmic delivery of curcumin

The transient precorneal retention time and low penetration capacity into intraocular tissues are the key obstacles that hinder the ophthalmic drug delivery of many therapeutic compounds, especially for drugs with poor solubility and permeability. To break the stalemate, N-acetyl-L-cysteine functionalized chitosan copolymer (CS-NAC), which exhibit marked bioadhesion and permeation enhancing effect, was synthesized. The curcumin encapsulated NLC (CUR-NLC) was produced and optimized followed by surface absorption of CS-NAC. After coating, changed particle size from 50.76 ± 2.21 nm to 88.64 ± 1.25 nm and reversed zeta potential from −20.38 ± 0.39 mV to 22.51 ± 0.34 mV was observed. The in vitro CUR release from NLC was slower than that of CUR-NLC and chitosan hydrochlorides (CH) coated NLC due to the inter and/or intramolecular disulfide formation of thiomers on the surface of nanocarriers. The modification also significantly enhanced transcorneal penetration compared with CH-NLC and the uncoated ones. The effect on bioadhesion and precorneal retention were evaluated by in vivo imaging technique and ocular pharmacokinetics studies revealing that the clearance of the formulations was significantly delayed in the presence of CS-NAC and the effect was positively related to the degree of thiolation. In summary, CS-NAC-NLC presented a series of notable advantages for ophthalmic drug application.

Application of lipid nanoparticles to ocular drug delivery

INTRODUCTION

Although eye drops are widely used as drug delivery systems for the anterior segment of the eye, they are also associated with poor drug bioavailability due to transient contact time and rapid washout by tearing. Moreover, effective drug delivery to the posterior segment of the eye is challenging, and alternative routes of administration (periocular and intravitreal) are generally needed, the blood-retinal barrier being the major obstacle to systemic drug delivery. Areas covered: Nanotechnology, and especially lipid nanoparticles, can improve the therapeutic efficiency, compliance and safety of ocular drugs, administered via different routes, to both the anterior and posterior segment of the eye. This review highlights the main ocular barriers to drug delivery, as well as the most common eye diseases suitable for pharmacological treatment in which lipid nanoparticles have proved efficacious as alternative delivery systems. Expert opinion: Lipid-based nanocarriers are among the most biocompatible and versatile means for ocular delivery. Mucoadhesion with consequent increase in pre-corneal retention time, and enhanced permeation due to cellular uptake by corneal epithelial cells, are the essential goals for topical lipid nanoparticle delivery. Gene delivery to the retina has shown very promising results after intravitreal administration of lipid nanoparticles as non-viral vectors.

Rationally designed nanocarriers for intranasaltherapy of allergic rhinitis: influence of carrier type on in vivo nasal deposition

The aim of this study is to develop a locally acting nasal delivery system of triamcinolone acetonide (TA) for the maintenance therapy of allergic rhinitis. The effect of encapsulating TA in different nanocarriers on its mucosal permeation and retention as well as in vivo nasal deposition has been studied. A comparative study was established between polymeric oil core nanocapsules (NCs), lipid nanocarriers such as nanoemulsion (NE), and nanostructured lipid carriers (NLCs). The elaborated nanocarriers were compared with TA suspension and the commercially available suspension "Nasacort(®)". The study revealed that NC provided the highest mucosal retention, as 46.14%±0.048% of the TA initial dose was retained after 24 hours, while showing the least permeation through the nasal mucosa. On the other hand, for TA suspension and Nasacort(®), the mucosal retention did not exceed 23.5%±0.047% of the initial dose after 24 hours. For NE and NLC, values of mucosal retention were 19.4%±0.041% and 10.97%±0.13%, respectively. NC also showed lower mucosal irritation and superior stability compared with NE. The in vivo nasal deposition study demonstrated that NC maintained drug in its site of action (nasal cavity mucosa) for the longest period of time. The elaborated polymeric oil core NCs are efficient carriers for the administration of nasally acting TA as it produced the least permeation results, thus decreasing systemic absorption of TA. Although NCs have been administered via various routes, this is the first study to implement the polymeric oil core NC as an efficient carrier for localized nasal drug delivery.

Nanoparticles prolong N-palmitoylethanolamide anti-inflammatory and analgesic effects in vivo

N-Palmitoylethanolamide showed great therapeutic potential in the treatment of inflammation and pain but its unfavourable pharmacokinetics properties will hinder its use in the clinical practice. A nanotechnology-based formulation was developed to enhance the probability of N-palmitoylethanolamide therapeutic success, especially in skin disease management. Lipid nanoparticles were produced and characterized to evaluate their mean size, ζ-potential, thermal behaviour, and morphology. The ability of N-palmitoylethanolamide to diffuse across the epidermis as well as anti-inflammatory and analgesic effects were investigated. Particles had a mean size of about 150 nm and a ζ-potential of -40 mV. DSC data confirmed the solid state of the matrix and the embedding of N-palmitoylethanolamide while electron microscopy have evidenced a peculiar internal structure (i.e., low-electrondense spherical objects within the matrix) that can be reliably ascribed to the presence of oil nanocompartments. Lipid nanoparticles increased N-palmitoylethanolamide percutaneous diffusion and prolonged the anti-inflammatory and analgesic effects in vivo. Lipid nanoparticles seem a good nanotechnology-based strategy to bring N-palmitoylethanolamide to clinics.

Supramolecular hydrogel of non-steroidal anti-inflammatory drugs: preparation, characterization and ocular biocompatibility

A supramolecular hydrogel based on a peptide (GFFY) and non-steroidal anti-inflammatory drugs (naproxen and ibuprofen) was synthesized for use as a topical gel.

Preparation, characterization and biocompatibility studies of thermoresponsive eyedrops based on the combination of nanostructured lipid carriers (NLC) and the polymer Pluronic F-127 for controlled delivery of ibuprofen

CONTEXT

Nanostructured lipid carrier (NLC) dispersions present low viscosity and poor mucoadhesive properties, which reduce the pre-corneal residence time and consequently, the bioavailability of ocular drugs.

OBJECTIVE

The aim of this study was to prepare thermoresponsive eyedrops based on the combination of lipid nanoparticles and a thermoresponsive polymer with mucomimetic properties (Pluronic® F-127).

MATERIALS AND METHODS

NLC_i dispersions were prepared based on the melt-emulsification and ultrasonication technique. Physicochemical and morphological characteristics of the colloidal dispersions were evaluated. The formulation was also investigated for potential cytotoxicity in Y-79 human retinoblastoma cells and the in vitro drug release profile of the ibuprofen was determined.

RESULTS

NLC_i showed a Z-average below 200 nm, a highly positive zeta potential and an efficiency of encapsulation (EE) of ∼90%. The gelification of the NLC_i dispersion with 15% (w/w) Pluronic® F-127 did not cause significant changes to the physicochemical properties. The potential NLC-induced cytotoxicity was evaluated by the Alamar Blue reduction assay in Y-79 cells, and no relevant cytotoxicity was observed after exposure to 0-100 µg/mL NLC for up to 72 hours. The optimized formulations showed a sustained release of ibuprofen over several hours.

DISCUSSION AND CONCLUSION

The strategy proposed in this work can be successfully used to increase the bioavailability and the therapeutic efficacy of conventional eyedrops.

Ophthalmic applications of lipid-based drug nanocarriers: an update of research and patenting activity

Ophthalmic diseases collect great attention by researchers and pharmaceutical technologists, since they can dramatically worsen the quality of life. Because of the limited duration of action on the eye surface, and anatomical/physiological barriers to drug penetration from it into the inner eye structures, conventional ocular formulations are generally unable to perform at their best. Nanotechnology approaches can represent a solution to improve the therapeutic efficiency, compliance and safety of ocular drugs. In this respect, lipid-based nanocarriers are among the most interesting systems. Their composition and production methods make them highly biocompatible and safe formulations. This review illustrates the developments achieved in ocular drug delivery using lipid-based nanocarriers, with a critical revision of recent scientific articles and filed patents.